The self-test verifies that components connected to the PIC24FJ64GA002 respond as expected. This test was successful and found no errors.

Control pin test

The self-test enables the auxiliary (AUX) pin, MODE LED, and voltage regulator control (VREG), and verifies that each pin went high. The CD4066 control pin (PULLUP) is held at 5volts with a pull-up resistor, so we test it high to see if the pull-up is working, and then low to see if the PIC pin is operating correctly.

If pull-up high fails, check R19.

Other errors could be a soldering defect or broken microcontroller.

Analog pin test

The four analog voltage monitors and the two power supplies are tested. The 3.3volt and 5volt supplies are enabled and checked for the correct voltage. The ADC and Vpullup pin monitors are connected to the power supplies in order to test their function, as well as verify the results of the power supply monitors.

If 5volt and Vpullup (or 3.3volts and ADC) both read 0volts, there could be a problem with the voltage regulator. Check VR3, VR4, C22, C24, R18.

If one shows a voltage, but the other doesn't, there could be a problem with the voltage monitor, the PIC microcontroller, or you forgot to connect the pins for self-test mode. Check R10-R16.

Bus pin check

The bus I/O pins and pull-up resistors are tested three ways. First, all bus pins are set high and verified without pull-up resistors. The pins then go low and the pull-up resistors are enabled to test open drain pin functionality. Finally, the pins are put in high-impedance mode to test the on-board pull-up resistors.

Open collector high failures could indicate a problem with the on-board pull-up resistors, or you forgot to connect the 5volt and Vpullup pins. Check R19, R20-R23, IC3.